In a housing of a mobile telephone terminal, for example, a dome-switch sheet is placed on a back surface of a keypad. The dome-switch sheet is formed by, for example, a flat flexible printed board, and is connected to a printed board incorporated in the mobile telephone terminal. Electronic components mounted on the printed board are connected. The dome-switch sheet is connected to the printed board by a flexible printed board. A base end of the flexible printed board extends in the dome switch sheet, and a leading end of the flexible printed board is fitted in a connector provided on the printed board. The keypad is connected to the electronic components on the printed board.
The connector has a housing. A receptacle is provided in the front of the housing and extends in the width direction of the housing. Conductive terminals are provided in the receptacle in a manner such as to point upward. The housing is connected to a lock plate that extends in the width direction of the housing and pivots on a pivot shaft. When the leading end of the flexible printed board is inserted in the receptacle, conductive pads of the flexible printed board are elastically received by the conductive terminals. The lock plate pivots to be pressed against the surface of the flexible printed board. Thus, the flexible printed board is clamped between the lock plate and the conductive terminals.
With reduction in size and thickness of the mobile telephone terminal, the space of the flexible printed board is limited. Even when the number of conductive pads increases, the space does not increase. Because of the limited space, for example, the conductive terminals are arranged in two lines in the width direction of the flexible printed board. Wiring patterns to be connected to the front line of conductive terminals are provided between the rear line of conductive terminals. As a result, the width of the wiring patterns is reduced markedly. When the flexible printed board is inserted, a pressing force acts on the flexible printed board from a rear end of the lock plate because of pivotal motion of the lock plate. When a great stress is generated at the boundary between the wiring pattern and the conductive pad, the wiring pattern is broken by cracking. Further, when the stress is great, the conductive pad is also broken.